Display element

Abstract

A display element in which reduced variation in color in the midtone has been achieved even when repeatedly driven is disclosed, comprising opposing electrodes and an electrolyte containing silver or a compound including silver in the chemical structure between the opposing electrodes, wherein the opposing electrodes are driven so that the silver is dissolved or deposited and the following requirement is satisfied: A 1/ A 2>4 in which A1 (mA/cm 2 ) is a maximum value of absolute values of an electric current applied between the opposed electrodes when driven in the direction of from a state of no silver being deposited on the side of the display electrode to that of the silver being deposited and A2 (mA/cm 2 ) is a maximum of absolute values of an electric current applied between the opposing electrodes when driven in the direction of from a state of no silver being deposited on the side of the display electrode to that of the silver being dissolved.

1. A display element comprising opposing electrodes and an electrolyte containing silver or a compound including silver in the chemical structure between the opposing electrodes, wherein the opposing electrodes are driven so that the silver is dissolved or deposited and the following requirement is satisfied:
     A 1 /A 2>4 
 
       wherein A1 (mA/cm 2 ) is a maximum of absolute values of an electric current applied between the opposed electrodes when driven in the direction of from a state of no silver being deposited on a display electrode side to that of the silver being deposited and A2 (mA/cm 2 ) is a maximum of absolute values of an electric current applied between the opposing electrodes when driven in the direction of from a state of no silver being deposited on the display electrode side to that of the silver being dissolved. 
     
     
       2. The display element as claimed in  claim 1 , wherein the opposing electrodes are driven in the direction of from a state of no silver being deposited on the side of the display electrode to that of the silver being dissolved before driven in the direction of from a state of no silver being deposited on the side of the display electrode to that of the silver being deposited. 
     
     
       3. The display element as claimed in  claim 1  wherein the following requirement is satisfied:
   1.2 ≦d/L≦ 100 
 
       wherein d (μm) is a distance between the opposed electrodes and L (μm) is a minimum of distances between adjacent electrodes on a non-observation side of the opposing electrodes. 
     
     
       4. The display element as claimed in  claim 1 , wherein the following requirement is satisfied:
   0.1≦Ra≦100
 
 
       wherein Ra (nm) is a surface roughness of an electrode on a non-observation side of the opposing electrodes. 
     
     
       5. The display element as claimed in  claim 1 , wherein the electrolyte comprises at least one compound represented by the formula (1) or (2) and at least one compound represented by the formula (3) or (4): 
       
         
           
           
               
               
           
         
       
       wherein L is an oxygen atom or CH 2 ; R 1  through R 4  are each a hydrogen atom, an alkyl group, an alkenyl group, an aryl group, a cycloalkyl group, an alkoxyalkyl group or an alkoxy group; 
       
         
           
           
               
               
           
         
       
       wherein R 5  and R 6  are each a hydrogen atom, an alkyl group, an alkenyl group, an aryl group, a cycloalkyl group, an alkoxyalkyl group or an alkoxy group;
   R 7 —S—R 8   formula (3)
 
 
       wherein R 7  and R 8  are each a substituted or unsubstituted hydrocarbon group, provided that when R 7  or R 8  combine with each other to form a S-containing ring, the ring is not an aromatic group; 
       
         
           
           
               
               
           
         
       
       wherein M is a hydrogen atom, a metal atom or a quaternary ammonium; Z is a nitrogen-containing heterocyclic ring; n is an integer of 0 to 5; R 9  is a halogen atom, an alkyl group, an aryl group, an alkylcarbonamido group, an arylcarbonamido group, an alkylsulfonamido group, an arylsulfonamido group, an alkoxy group, an aryloxy group, an alkylthio group, an arylthio group, an alkylcarbamoyl group, an arylcarbamoyl group, a carbamoyl group, an alkylsulfamoyl group, an arylsulfamoyl group, a sulfamoyl group, a cyano group, an alkylsulfonyl group, an arylsulfonyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkylcarbonyl group, an arylcarbonyl group, an acyloxy group, a carboxyl group, a carbonyl group, a sulfonyl group, an amino group, a hydroxy group or a heterocyclic group, provided that when n is 2 or more, R 9 s may be the same or different or may combine to form a condensed ring. 
     
     
       6. The display element as claimed in  claim 1 , wherein the display element meets the following relation (1):
   0≦[X]/[Ag]≦0.01  relation (1)
 
 
       wherein [X] is a molar concentration (mole/kg) of halogen ions or halogen atoms contained in the electrolyte and [Ag] is a total molar concentration (mole/kg) of silver contained in the electrolyte or silver included in the compound including silver in the chemical structure.